下载文档原格式
材料化工专业英语生词本Synthesis 合成Properties 性质Anatase 锐钛矿rutile 金红石brookite板钛矿Crystalline 结晶的nanometer 纳米nanorods/wires纳米棒/线nanocrystals 纳米晶体nanocarriers 纳米载体nanoparticles （NPs）纳米颗粒nanocomposite纳米复合Hierarchical Nanostructures 分层纳米材料titanium dioxide TiO2 polymorphs of titania 多晶型 TiO2 amorphous 非晶的Three-dimensional 3Dfacile and controlled 容易控制hydrothermal 热液的annealing 退火investigate 调查，研究radially 放射状地petal 花瓣thin 薄的thick 厚的morphology 形态The surface area 表面积adsorption-desorption 吸附-解析（ads）orption isotherms 吸附等温线the Brunauer-Emmett-Teller BET 比表面积测试法specific surface areas 比表面积sensitivity 灵敏、灵敏性ethanol 乙醇、酒精ethylene glycol 乙二醇EG化学式C2H6O2分子式：HOC2H4OHsensor 传感器、感应器solar cells太阳能电池biosensors 生物传感器catalyst 催化剂Catalysis 催化photo-catalytic 光催化的inorganic 无机的objective 目标optimize 使完善、使优化optical 光学的magnetic 磁的application 应用bandgap 带隙transition metal oxides 过渡金属氧化物paint 油漆、颜料gas sensor 气敏元件、气敏传感器Li-ion battery 锂离子电池Electrochromic 电致变色的Photochromism 光致变色macro/mesoporous materials 宏/介孔材料CVD(Chemical Vapor Deposition, 化学气相沉积)Anodic 阳极的hydrothermal method 水热法Template 样板、模板oriented attachment 定向附着primary nanoparticle 初级纳米粒子anisotropic非等方性的、各向异性的capping agents 盖髓剂kirkendall effect柯肯达尔效应tetragonal structure 四方结构photovoltaic cells 光伏电池smart surface coatings 智能表面涂层single-phase 单相precursor 先驱、前导Herein 在此处、鉴于、如此 Nanoflakes 纳米片metal-enhanced fluorescence 金属增强荧光fluorophores 荧光团The Royal Society of Chemistry 英国皇家化学学会ESI (Electronic Supplementary Material) 电子补充材料 Innovative 创新的 Polymer 聚合物 Chemical 化学品 Silica 硅 FITC （fluorescein isothiocyanate ）荧光异硫氰酸酯EiTC ( Eosin isothiocyanate ) 异硫氰酸曙红Fluorescence spectra 荧光光谱 control sample 对照样品 Dissolve 溶解Characterization 表征 analytical grade 分析纯 ethanol 乙醇ethylene glycol 乙二醇 ammonia aqueous solution （28 wt %）氨水溶液（100公斤里含28公斤） acetone 丙酮分子式：C3H6O 简式：CH3COCH3EtoH 乙醇 （ PS ：Et 代表乙基CH3CH2- Me 代表甲基CH3-）TEOS （tetraethyl orthosilicate ） 原硅酸四乙酯the TEOS concentration TEOS 浓度 CTAB （hexadecyltrimethylammonium bromide ） 十六甲基溴化铵The CTAB surfactant CATB 表面活性剂Sinopharm Chemical Reagent Co. 国药集团化学试剂有限公司Polyvinylpyrrolidone (PVP, Mw = 55000) 聚乙烯吡咯烷酮（PVP ，MW = 55000=兆瓦，百万瓦特(megawatt)）Rhodamine B (Rh B) 玫瑰精，若丹明B poly(allylamine hydrochloride) (PAH, Mw = 56000) 聚（烯丙胺盐酸盐） Deionized water 去离子水PAH （ polycyclic aromatic hydrocarbon ）多环芳族烃 Via 经由、通过the three-neck flask 三颈烧瓶 oil bath 油浴precipitate 沉淀centrifugation 离心分离 rpm 每分钟转数 core-shell 核-壳a surfactant-templating sol-gel approach 表面活性剂模板溶胶 - 凝胶法homo-dispersed solution 均聚物分散夜agitate 搅拌ultrasonically and mechanically 超声波地、机械地solvent extraction method 溶剂萃取法reflux 回流an impregnation method 浸渍方法 vial 小瓶 dilute 稀释composite 合成物、复合物TEM （Transmission electron microscopy ）透射电子显微镜copper grids 铜网carbon films 碳膜SEM（Scanning electron microscopy）扫描电子显微镜Spray 喷FESEM（Field-emission scanning el ectron microscopy）场发射扫描电子显微镜LCSM(Laser confocal scanning microscopy )激光共聚焦扫描显微镜X-ray diffraction (XRD) X 射线衍射X-ray diffractometer X射线衍射仪Nitrogen 氮Micromeritcs n. 微晶（粒）学，粉末工艺学；粉体学degas除去瓦斯vacuum 真空BET(The Brunauer-Emmett-Teller) pore volume 孔体积spectrofluorometer 荧光分光剂spectrophotometer分光光度计bandpass 带通PMT voltage （Photomultiplier Tube）光电倍增管电压Confocal luminescence images共聚焦荧光图像Silver 银silica spacer 硅垫片fabricate制造; 伪造; 组装; 杜撰the metal-enhancedMEF（the metal-enhanced fluorescence ）金属增强荧光Fluorescence quenching 荧光猝灭FRET (Fo¨rs ter resonance energy transfer )福斯特共振能量转移Optimization 最佳化; 最优化excited-state 激发态plasmon 等离子基元quantum yields 量子产率quantum dots 量子点resonance n.共振，共鸣, 反响, 回声donor–acceptor pairs 给体- 受体对proximity 接近efficiency 效率the transfer distances 传输距离deposite 被沉淀，存放plastic planar substrate塑料平面基板photoluminescence (PL)光致发光luminescent 发光的single nanoparticle sensing单一纳米粒子传感dielectric电介质; 绝缘体adj.非传导性的RE complexes稀土复合Polyelectrolytes聚合高分子电解质Electrolyte电解质Multilayer 多层Concentric 同中心的functionalized organic molecules 官能有机分子conjugation 结合，配合tedious and fussy繁琐和挑剔obstacle n.障碍, 阻碍, 妨害物controlled release,控释detection and probe applications 检测和探头应用general一般的; 综合的; 普通的universal普遍的, 通用的, 全体的Inspired 启发Possess 拥有Pore 孔drugs and macro-molecules 药物和大分子herein在此处, 鉴于, 如此Ag@SiO2@mSiO2（Ag-core@silica-spacer@mesoporo us silica ）The preparation procedure编制程序Water-soluble可溶于水的; 水溶性的，微溶于水A high-temperature solvothermal method一种高温溶剂热法Solvent 溶剂Esolution 分辨率twinned structures 联动结构，孪生结构concentration 浓度tune 调节is ascribed to 归因于dilute稀释spherical morphology 球形形态type-IV curves IV型曲线polyelectrolytesodium chloride食盐; 氯化钠plasmonic absorption电浆吸收an intuitive way 以直观的方式unambiguous 不含糊的, 明白的demonstrate 证明antibody 抗体NSF（National Sanitation Foundation）美国国家卫生基金会PRC(The People's Republic of China)中华人民共和国Shanghai Municipality上海市Shanghai Leading Academic Discipline Project上海重点学科建设项目Tri-functional hierarchical三官能分层DSSCs（dye-sensitized solar cells）染料敏化太阳能电池DOI（Digital Object Unique Identifier）是一种数字对象标识体系acid thermal method 酸热法titanium n-butoxid正丁醇钛acetic acid乙酸、醋酸kinetic 动能light-scattering 光散射photoelectrodes 光电极opto-electronic 光电的calcine煅烧short-circuit photocurrent density短路光电流密度open-circuit voltage开路电压compared to 相比，把什么比作什么electron 电子recombination rates 重组率oxide 氧化物inorganic 无机的sub-microspheres 亚微球beads珠子To date 迄今a ruthenium complex light-harvester钌络合物的光收割机volatile 挥发性的photoanode光阳极superior 好的，卓越的photons 光子photovoltaic performance光伏性能In addition to 除。
微纳米流动和核磁共振技术英文回答：Microfluidics and nuclear magnetic resonance (NMR) are two important technologies that have revolutionized various fields of science and engineering.Microfluidics refers to the study and manipulation of fluids at the microscale level, typically in channels or chambers with dimensions ranging from micrometers to millimeters. It allows precise control and manipulation of small volumes of fluids, enabling a wide range of applications such as chemical analysis, drug delivery systems, and lab-on-a-chip devices. Microfluidic devices are often fabricated using techniques such as soft lithography, which involve the use of elastomeric materials to create microchannels and chambers.NMR, on the other hand, is a powerful analytical technique that utilizes the magnetic properties of atomicnuclei to study the structure and dynamics of molecules. It is based on the principle of nuclear spin, which is the intrinsic angular momentum possessed by atomic nuclei. By subjecting a sample to a strong magnetic field and applying radiofrequency pulses, NMR can provide information about the chemical composition, molecular structure, and molecular interactions of the sample. NMR has diverse applications in fields such as chemistry, biochemistry, medicine, and materials science.Microfluidics and NMR can be combined to create powerful analytical tools for studying various biological and chemical systems. For example, microfluidic devices can be used to precisely control the flow of samples and reagents, while NMR can provide detailed information about the composition and structure of the samples. This combination has been used in the development ofmicrofluidic NMR systems, which allow rapid and sensitive analysis of small sample volumes. These systems have been applied in areas such as metabolomics, drug discovery, and environmental monitoring.中文回答：微纳米流体力学和核磁共振技术是两种重要的技术，已经在科学和工程的各个领域引起了革命性的变化。
一种噻吩基双偶极半菁与普鲁士蓝的静电自组装薄膜王志平;罗虹;高丽华;王科志【摘要】We successfully prepared a novel inorganic-organic hybrid electrostatically self-assembled multilayer film by alternately depositing Prussian blue (PB) and a thiophene-containing hemicyanine. The optical, electrochemical, and photoelectrochemical properties of the as-prepared films were studied by UV-visible absorption spectroscopy, cyclic voltammetry, and photoelectrochemical experiment. Linear increases in the absorbances at 376 and 698 nm with the number of deposited layers, up to at least 8 layers, indicated that film deposition was uniform and reproducible. The PB in the prepared films was found to occur surface-confined rather than diffusion-controlled redox reactions and the peak currents increased with an increase in the number of layers up to 5 layers. Upon irradiation with 100 mW· cm-2 white light the films exhibited stable and reproducible cathodic photocurrents, which increased as the number of layers increased up to 4 layers. A maximum photocurrent density of 0.28 μA· cm-2 was found for the four-layer film at a bias voltage of -0.4 V vs the saturated calomel electrode.%通过交替沉积普鲁士蓝和一种含噻吩的半菁,制备了一种新的无机-有机杂化静电自组装膜.用紫外-可见吸收光谱、循环伏安技术和光电化学实验对薄膜进行了表征或光电性质研究.376和698 nm处薄膜的吸光度随薄膜层数增加线性增加,表明薄膜的沉积是均匀和可重复的.薄膜中的普鲁士蓝具有良好的表面控制而非扩散控制的电化学活性.膜的层数从1增加至5时,阳极峰电流随膜层数增加而线性增加.100 mW·cm-2的白光照射下,薄膜产生稳定的阴极光电流,随层数增加线性增长,层数增加到4层时,光电流达到最大值.饱和甘汞电极为参比电极,-0.4 V偏压下,4层薄膜产生的光电流密度高达0.28 μA·cm-2.【期刊名称】《物理化学学报》【年(卷),期】2011(027)003【总页数】5页(P754-758)【关键词】半菁;自组装膜;循环伏安;紫外可见光谱;噻吩;光电化学性质【作者】王志平;罗虹;高丽华;王科志【作者单位】北京师范大学化学学院,北京100875;集宁师范学院,内蒙古集宁012000;北京师范大学化学学院,北京100875;北京工商大学化学与环境工程学院,北京100048;北京师范大学化学学院,北京100875【正文语种】中文【中图分类】O646Abstract: We successfully prepared a novel inorganic-organic hybrid electrostatically self-assembled multilayer film by alternately depositing Prussian blue(PB)and a thiophene-containing hemicyanine.Theoptical,electrochemical,and photoelectrochemical properties of the as-prepared films were studied by UV-visible absorption spectroscopy,cyclic voltammetry,and photoelectrochemical experiment.Linear increases in the absorbances at 376 and 698 nm with the number of deposited layers,up to at least 8 layers,indicated that film deposition was uniform and reproducible.The PB in the prepared films was found to occur surface-confined rather than diffusion-controlled redox reactions and the peak currents increased with an increase in the number of layers up to 5 layers.Upon irradiation with 100 mW·cm-2white light the films exhibited stable and reproducible cathodic photocurrents,which increased as the number of layers increased up to 4 layers.A maximum photocurrent density of 0.28 μA·cm-2was found for the four-layer film at a bias voltage of-0.4 Vvsthe saturated calomel electrode.Key Words:Hemicyanine;Self-assembled film;Cyclic voltammetry;UV-visible spectrum;Thiophene;Photoelectrochemical propertyDecher1发展的以静电作用力为驱动、将阴阳离子交替沉积吸附制备自组装膜的技术,由于具有方法简单、厚度可控、性质稳定和高度的分子水平组装能力的特点,已引起科学工作者的广泛关注,而有机-无机杂化材料的静电自组装膜已成为目前研究的热点.2,3半菁化合物是备受关注的二阶非线性光学和光电转换材料,过去的十几年的时间里主要采用Langmuir-Blodgett(LB)技术制备多层薄膜,4-10但LB技术具有仪器昂贵、制备费时和薄膜不够稳定等缺点.近年我们曾报道了双偶极半菁和Ru(II)配合物与杂多/同多阴离子、普鲁士蓝和WO3形成的静电自组装多层薄膜,表现出诱人的二阶非线性光学性质和光电转换性质.11-19噻吩是重要的导电聚合物单体,在发光二极管、太阳能电池和场效应晶体管领域有重要应用前景.20普鲁士蓝是一类重要的电致变色、传感和磁学材料.21-24但含噻吩的半菁静电自组装膜未见文献报道.本文报道一种含噻吩基的新双偶极半菁衍生物与普鲁士蓝形成的静电自组装膜以及薄膜的氧化还原和光电化学性质,旨在为这种原料易得、制备简单的有机-无机复合的纳米薄膜材料在多领域的应用提供重要的基础实验数据.用于成膜的含噻吩基双偶极半菁(分子结构示于图1,简记为ABr2),按文献5,11报道的方法合成,经元素分析和核磁共振谱表征.普鲁士蓝{KFeIII4[FeII(CN)6]3}(简记为KFeIII-FeII)按文献14报道的方法合成.GBC Cintra 10e型紫外-可见分光光度计(澳大利亚);pHS3酸度计(上海精密科学仪器有限公司);CHI420电化学分析仪(上海辰华仪器公司);采用三电极系统,覆盖有自组装膜的氧化铟-氧化锡(ITO)玻璃为工作电极,铂丝为对电极,饱和甘汞电极为参比电极,支持电解质为0.5 mol·L-1的Na2SO4溶液(pH=1.93).白光光源(光强为100 mW·cm-2)为配有红外和紫外截止滤光片的500 W高压氙灯光源系统(北京畅拓科技有限公司),薄膜光照的有效面积为0.28 cm2.将石英和玻璃基片分别用98%浓硫酸:30%双氧水(体积比为3:1)和25%氨水:30%双氧水:水(体积比为1:1:5)清洁和亲水处理;ITO玻璃用氢氧化钠的饱和乙醇溶液清洁和亲水处理.处理后的石英和ITO基片按图2所示的途径途组装薄膜.首先按文献3,7,8方法进行表面硅烷化和氨基质子化,然后依次分别浸入1.0 mmol·L-1普鲁士蓝水溶液30 min和1.0 mmol·L-1ABr2水溶液50 min,每次取出后用pH=3.0的去离子水冲洗干净,空气吹干;重复图2所示的步骤2、3即可得到静电自组装多层膜.普鲁士蓝水溶液、半菁ABr2水溶液和9层[(FeIII-FeII)-/A2+]9膜的紫外-可见吸收光谱的比较如图3所示.从图中可见,ABr2在378 nm处出现了1个π→π*吸收峰,4普鲁士蓝在684 nm处出现了Fe(II)与Fe(III)间的电荷转移跃迁吸收峰,25而自组装多层膜在376和698 nm处明显出现了两个最大吸收峰,其中376 nm处的吸收峰和ABr2水溶液的吸收特征相似,698 nm处的吸收峰与普鲁士蓝的吸收特征相似,说明阴阳离子已组装到基片上.值得注意的是薄膜的吸收峰较普鲁士蓝发生了近14 nm的红移,可能源于膜中A2+与普鲁士蓝间发生电荷转移.21图4为不同层数[(FeIII-FeII)-/A2+]n(n=1-8)膜的紫外可见吸收光谱.从图中可见,不同层数的薄膜的吸收峰基本保持不变,表明层间分子的相互作用不随膜层数的增加而变化;在376和698 nm处的吸光度随着膜层数的增加而线性增加(见图4插图),表明两种成膜组分已被成功组装上去,且薄膜的沉积是均匀和可重复的.因为基片的两面均有膜,由376 nm处的吸光度随层数增加的直线斜率0.00576除以2,可得出单层膜[(FeIII-FeII)-/A2+]1膜的吸光度A=2.9×10-3,由ABr2水溶液在376 nm处的摩尔消光系数ε=5.4×104L·mol-1·cm-1,根据朗伯-比耳定律可推出半菁分子表面覆盖率Γ=10-3A/ε,其中A为每层的吸光度,ε为ABr2水溶液的摩尔消光系数.求得Γ=5.3×10-11mol·cm-2,此值大于我们最近报道的双核钌配合物与普鲁士蓝形成的静电自组装膜的表面覆盖率3.7×10-11mol·cm-2,14表明薄膜的致密性较好.同理,由在698 nm处单层膜的吸光度值4.0×10-3以及普鲁士蓝水溶液的摩尔消光系数值3.0×104L·mol-1·cm-1,求得普鲁士蓝在膜中的表面覆盖率为1.3×10-10mol·cm-2,约为半菁分子表面覆盖率值的2.5倍.显然,成膜材料的分子体积是控制每个成膜组分多少的关键因素,另外膜中组分间的电荷转移通常也是导致膜中组分非整比的因素.图5为以覆盖有4层[(FeIII-FeII)-/A2+]4膜的ITO基片为工作电极,饱和甘汞电极为参比电极,铂丝为对电极,电解液为0.5 mol·L-1的Na2SO4溶液(pH=1.93),在60-200 mV·s-1的扫描速率下的循环伏安曲线.可见薄膜分别在半波电位E1/2=0.015和0.97 V处出现两对氧化还原峰,可分别指认为如方程(1)和(2)所示普鲁士蓝PB被还原为Everitt盐ES(过程I)和PB被氧化为普鲁士黄PY(过程II)的两个过程:26如图5内插图所示,峰电流与扫描速率成正比,表明为表面控制而非扩散控制的氧化还原过程.图6为不同层数薄膜[(FeIII-FeII)-/A2+]n(n=1,2,3,5)的循环伏安曲线.由图6及其插图所示,膜的层数从1增加到5时,普鲁士蓝在膜中的氧化还原反应阳极峰电流随膜层数增加而线性增加.如图7(A)所示,-0.4 V偏压下,100 mW·cm-2白光照射2层薄膜[(FeIII-FeII)-/A2+]2产生较为稳定的阴极光电流,光电流达37 nA,明显有别于没有沉积薄膜的空白ITO电极产生的可忽略的微弱光电信号,可证实光电信号来自组装的薄膜.但光电流信号强度较我们最近研究的几种光电化学体系产生的光电流低.14,15,18可能源于本文研究的半菁吸光能力较差.偏压对光电流的影响研究表明,偏压越负,光电流越大,进一步证实为阴极光电流.薄膜产生的阴极光电流随膜层数增加而增加(光电流密度可达0.28 μA·cm-2),膜层数达4层后进一步增加层数,光电流减小(图7(B)). 紫外-可见吸收光谱、循环伏安技术和光电化学实验表明,能成功地通过静电自组装技术制备含有新型噻吩双偶极半菁和普鲁士蓝的多层超薄膜.薄膜在376和698 nm处的吸光度随着膜层数的增加而线性增加,测得膜中半菁和普鲁士蓝的表面覆盖率分别为5.3×10-11和1.3×10-10mol·cm-2,表明薄膜沉积均匀致密.循环伏安实验观察到两对分别指认为普鲁士蓝PB被还原为Everitt盐和PB被氧化为普鲁士黄的两对氧化还原峰,氧化还原过程为表面控制,且峰电流随层数增加而增加.白光照射下,薄膜能产生稳定的阴极光电流,4层薄膜的光电流密度可达0.28 μA·cm-2.【相关文献】(1) Decher,G.Science 1997,277,1232.(2)Zhang,X.;Chen,H.;Zhang,mun.2007,1395.(3)Wang,K.Z.;Gao,L.H.Mater.Res.Bull.2002,37,2447.(4)Lang,A.D.;Zhai,J.;Huang,C.H.;Gan,L.B.;Zhao,Y.L.;Zhou,D.J.;Chen,Z.D.J.Phys.Chem.B 1998,102,1424.(5)Yao,Q.H.;Shan,L.;Li,F.Y.;Yin,D.D.;Huang,C.H.Acta Phys.-Chim.Sin.2003,19,635.[姚巧红,单路,李富有,尹冬冬,黄春辉.物理化学学报,2003,19,635.](6)Wang,K.Z.;Huang,C.H.;Xu,G.X.;Xu,Y.;Liu,Y.Q.;Zhu,D.B.;Zhao,X.S.;Xie,X.M.;Wu.N.Z.Chem.Ma ter.1994,6,1986.(7)Wang,K.Z.;Huang,C.H.;Xu,G.X.;Zhao,X.S.;Xia,X.H.;Wu,N.Z.;Xu,L.G.;Li,T.K.Thin Solid Films 1994,252,139.(8)Wang,K.Z.;Huang,C.H.;Xu,G.X.;Wang,R.J.Polyhedron 1995,14,3669.(9)Wang,K.Z.;Jiang,W.;Huang,C.H.;Xu,G.X.;Xu,L.G.;Li,T.K.;Zhao,X.S.;Xie,X.M.Chem.Lett.1995,1 761.(10)Wang,K.Z.;Huang,C.H.;Zhou,D.J.;Xu,G.X.;Xu,Y.;Li,Y.Q.;Zhu,D.B.;Zhao,X.S.;Xie,X.M.Solid State Commun.1995,93,189.(11)Wang,L.Y.;Wang,K.Z.;Gao,L.H.Acta Chim.Sin.2003,61,1877.[王丽颖,王科志,高丽华.化学学报,2003,61,1877.](12)Gao,L.H.;Hu,X.J.;Zheng,D.S.;Guo,Y.;Wang,K.Z.J.Nanosci.Nanotechnol.2008,8,1355.(13)Gao,L.H.;Wang,K.Z.;Wang,L.Y.J.Nanosci.Nanotechnol.2010,10,2018.(14)Ju,C.C.;Luo,H.;Wang,K.Z.J.Nanosci.Nanotechnol.2010,10,2053.(15)Zou,X.;Fan,Y.;Zhuang,M.Y.;Peng,J.;Wang,K.Z.J.Nanosci.Nanotechnol.2010,10,2203.(16)Zhang,Y.Q.;Gao,L.H.;Wang,K.Z.;Gao,H.J.;Wang,Y.L.J.Nanosci.Nanotechnol.2008,8,1248.(17)Wang,Y.B.;Xia,J.Y.;Gao,L.H.;Wang,K.Z.Chem.J.Chin.Univ.2007,28,1175.[王宜冰,夏即雅,高丽华,王科志.高等学校化学学报,2007,28,1175.](18)Zhou,X.;Fan,Y.;Zhuang,M.Y.;Peng,J.;Gao,L.H.;Wang,K.Z.Acta Chim.Sin.2010,68,2250.[邹旭,范娅,庄敏阳,彭景,高丽华,王科志.化学学报,2010,68,2250.](19)Zhang,Y.Q.;Gao,L.H.;Duan,Z.M.;Wang,K.Z.;Wang,Y.L.;Gao,H.J.Acta Chim.Sin.2004,62,738. [张玉琦,高丽华,段智明,王科志,王业亮,高鸿均.化学学报2004,62,738.](20) Mishra,A.;Ma,C.Q.;Baeuerle,P.Chem.Rev.2009,109,1141.(21) Karyakin,A.A.Electroanalysis 2001,13,813.(22) Dei,A.Angew.Chem.Int.Edit.2005,44,1160.(23) Ricci,F.;Palleschi,G.Biosens.Bioelectron.2005,21,389.(24) Itaya,K.;Uchida,I.;Neff,V.D.Accounts Chem.Res.1986,19,162.(25) Robin,M.B.Inorg.Chem.1962,1,337.(26) Dostal,A.;Meyer,B.;Scholz,F.;Bond,A.M.;Marken,F.;Shaw,S.J.J.Phys.Chem.1995,99,2096.。
Magnetic D evices for a Beam Energy RecoveryTHz Free Electron LaserR. R. S. Caetano¹, G. Cernicchiaro², R. M. O. Galvão³1 2Universidade Federal do Rio de Janeiro,Macaé, R J, Bra z il, rcaetano@macae.ufrj.brCoordenação de Física Aplicada, Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro, RJ, Bra z il, geraldo@cbpf.br3Instituto de Física USP, São Paulo, SP, Bra z il.Abstract:This paper presents a numerical analysis of magnetic devices, dipole, quadrupole and undulator and a THz Free Electron Laser (FEL) electron-beam recovery system. Free Electron Laser are an important source of coherent radiation being used in the study of chemical properties of substances, thus being an important tool for various fields of science such as condensed matter physics, chemistry, biology and medicine. The magnetic device of this simulation is to contribute to the proposed deployment of a national laboratory for multiuser application and development of a recovery system FEL to operate in the far infrared range between 0.3 to 1.2 THz.Keywords: Free Electron Laser THz, magnetic device, simulation in COMSOL.1.IntroductionFree electron laser can be used are in spectroscopy thus have applications in scientific fields such as medicine, chemistry, condensed matter and biology [1]. Thus the Brazilian Center for Physics Research (CBPF) proposed a construction project of a Free Electron Laser (FEL) using the components of a Free Electron Laser of the College of Optics & Photonis (CREOL). The free-electron laser operating in the far infrared range working with wavelengths in the range of 200-600 micrometers. The equipment consists of a linear accelerator that generates electrostatic energy up to 1.7 MeV, a magnetic undulator, which is designed with permanent magnets made from neodymium iron boron (NdFeB) with 185 periods with a wavelength of 8 mm length of 1486 mm and a distance between the undulator cassette (gap) of 6 mm. Has magnetic dipoles and quadrupoles working in optics from the electron beam. The vacuum system is formed by mechanical, ionic pumps and turbomolecular [2], control is being developed for the LabView platform.This paper focuses on the numerical analysis using the COMSOL software of magnetic elements that are the dipole, quadrupole and undulator. These components work changing the trajectory and the size of the electron beam.2.Theory2.1 DipoleT he magnetic dipole is an element that has the function deflect the electron beam [3]. The dipole magnetic field is generated by the electric current passing through the coils. This current in solenoid generates a magnetic flux in the iron core creating a unidirectional magnetic field in between irons given by the right hand rule. The magnitude of the magnetic field can be extracted by Ampere's law gives us the relationship between the electric current and the magnetic field.Figure 1: Magnetic dipole.The dipole magnetic field is given by equation 1 where n is the number of turns, the electrical current I, is the distance between the irons and is the permeability of air.( 1)2.2 QuadrupoleT his component consists of four poles formed by rectangular hyperbolas with alternating magnetic fields, your objective is to change the diameter of the electron beam. The geometry of the quadrupole makes the magnetic field in the core is zero and the magnetic field is generated by modulo magnitude of the field in the x-axis and y-axis [3].Figure 2: Magnetic quadrupole.The quadrupole magnetic field can be calculated from the integration by Ampere's law.( 2)The magnetic field consists of two quadrupole components in the x and y axis, there is a resulting gradient g [T/ m]. Thus, the magnetic field in the x and y axes can be given by the equations , where , and the equation of the resulting magnetic field is equal to:( 3)2.3 UndulatorThe undulator is a mechanical structure consisting of periodic magnets with alternating poles, separated by a distance called (gap). These magnets are made of magnetic material pure permanent magnetic (PPM). This structure causes synchronous radiation be concentrated in a beam, thus reducing the radiation loss.Figure 3: Description of the undulator magnetic.The magnetic undulator field is perpendicular to the x axis, and the direction of the z-axis. Because the poles are alternating magnetic field in the undulator has a sinusoidal behavior as can be seen in equation 4. [4]. Where is the wavelength of the undulator and is the initial magnetic field. In equation 5 we have the initial magnetic field which is a ratio between the gap and the wavelength.(4)(5) e of COMSOL MultiphysicsThe numerical analysis of the dipole, quadrupole and undulator were built using the module AC/DC COMSOL multiphysics. To calculate the magnetic field in the dipole and quadrupole magnetic field the tool was used with the equation 6. In the undulator, the calculation of the initial magnetic field was carried out with the magnetic field in the current tool with the equation 7.(6)(7)3.1 DipoleThe geometry of the dipole was constructed in 3D and has two types of materials are iron, which comprises all the dipole and charge air by the cylindrical shell. Infinite element domain was used for the cylindrical shell for emulating an infinite open space causing all numerical analysis considers the limited space as being infinite.Figure 4. 3D geometry of the magnetic dipole.The interface was used for the dipole Magnetic Field <Ampere Law for the iron structure and for calculating coil was used in Magnetic Field <muti-turn coil <Coil Current Calculation which calculate the magnetic field in the coil according to the current electrical and number of turns. The dipole has 877 turns and the maximum current is 2.5 A.Figure 5. Coil Current Calculation in dipole magnetic.Dipole in the fine mesh, which corresponds to 61114 domain element, boundary element 9728, 1039 edge element was used. The study used for the calculation of the dipole was the Stationary Parametric Sweep and the electric current was applied in order to have values of -2.5 A to +2.5 A.Figure 6: mesh magnetic Dipole.3.2 QuadrupoleThe quadrupole was developed in 3D for its construction it was done primarily in 2D and using the Work Plane tool, after it was extruded to 3D format.Figure7. Quadrupole magnetic geometric in 2D.Figure 8. 3D geometry of the magnetic quadrupole.The materials used in the quadrupole are air and iron and infinite element domain was appliedto the cylindrical shell. To calculate the magneticfield of the quadrupole physical Magnetic Field <Ampere Law, which calculates the magnetic field from the magnetization and uses equation was used , where N is the number of turns, I is the electric current, A is the area and V is the volume of the coil. In the case of quadrupole have 344 turns and the electrical current worth 2.5 A. The magnetization in the quadrupole is oriented in the x and z axes have that each pole has a different orientation.Quadrupole in the mesh extremely fine,which corresponds to 749885 domain element, boundary element 58352, 2772 edge element was used. The study used for the calculation of the quadrupole was the Stationary Parametric Sweep and the electric current was applied in order to have values of -2.5 A to +2.5 A.Figure 9: mesh magnetic quadrupole.3.3 UndulatorFor this work was a session of 3D undulator built with 400 mm in length and can change the wavelength and the distance of the gap. Undulator possessed these variations to resemble the original equipment. The initial magnetic field generated in the undulator does not depend on the distance of the gap but wavelength (equation 5)and thus it is possible to make a comparison between the simulation and the experiment.The materials used were a NdFeB magnetic material is (33SH) and those manufactured with the air gaps 1010 steel, their averages are: x = 10.5 mm, y = 1.3 mm and z = 25 mm and x = 30mm, y = 2 7 mm and z = 13 mm, respectively [5]. On the external surface that is a spherical vacuum volume 220 mm radius of 5mm layer was used.Figure 10. 3D geometry of the magnetic Undulator.T he magnetic field of the undulator was obtained using the Magnetic Field, No current Physical<Magnetic Flux. When applying a magnetic field in a material, the resulting field B is the sum of the applied field H and the field of the magnetized material, as in Equation 8.( 8)Magnetic materials have hysteresis magnetization curves called reduce to zero the magnetic field applied, as can be seen in equation 9 [6].( 9)The magnetization is added in Magnetic flux Conservation, as the magnetization of the magnets are oriented alternately is necessary to indicate the direction of magnetization in this case, the direction is along the x axis. The mesh used was extra fine, possessing 5842814 domain boundary elements 681 250 and 80 793 edge andthe study used was stationary.Figure 11. Mesh Undulator magnetic.6.0 Results 6.1 DipoleThe simulation dipole was constructed to compare the value of the modulus of the magnetic field with the experimental value in Figures 12 and 13 have the simulation results.Figure 12. Magnetic Flux density in an dipolemagnetic device.Figure 13. Graph magnetic field x current electric indipole.Table 1: Comparison of the magnetic field obtained from the simulation and experimental analysis in the dipole magnetic device.The magnetic field values are obtained for the maximum value of electric current of 2.5 A. Thus the table 1 it can be seen that the threevaluesarecloseto a percentage error of 3% between experiment and COMSOL. 6.2 QuadrupoleThe simulation quadrupole was constructed to compare the value of the modulus of the magnetic field with the experimental value in Figures 14 and 15 have the simulation results.Figure 14. Magnetic Flux density in an quadrupolemagnetic device.Figure 15. Graph magnetic field x current electric inquadrupole.Table 2: Comparison of the magnetic field obtained from the simulation and experimental analysis in the quadrupole magnetic device.The magnetic field values are obtained for the maximum value of electric current of 2.5 A. Thus the table 2 it can be seen that the three values are close to a percentage error of 1,9 % between CREOL and experiment.6.3 UndulatorThe simulation study of the undulator was developed for the x axis and y axis. In Figures 16, 17, 18 and 19 have a magnetic field initial described in the two axes respectively.Figure 16. Magnetic Flux density in an undulator magnetic device (front view). Figure17. Magnetic field of the undulator gap measured in the z axis direction with respect to distance in the y direction.Figure 18. Magnetic Flux density in an undulator magnetic device (side view).In Figure 19 we have the magnetic field in the undulator which is a sine function according to equation 10, so this simulation is in agreement with theory. In Table 3it canbe observedthat the values stipulated by the project, experiment and COMSOL, so it is possible that there is an error 1% compared to COMSOL and experiment.Figura 19.Undulator magnetic field measured at the gap in the z direction as a function of distance in the x direction.Table 3: Comparison of the magnetic field obtained from the simulation and experimental analysis in the undulator magnetic device.7.0 ConclusionIn this paper we present 3D simulations of the dipole, quadrupole and undulator magnetic elements that are owned by a Thz Free Electron Laser. The results have to numerical simulation results are in agreement with experiment validating the paper. To the next module using the practical tracing in COMSOL, an electron beam will be added with the aim of studying the behavior of the electron beam in magnetic elements.8 Reference[1] S rinivas Krishnagopal*, Vinit Kumar†,Sudipta Maiti, S. S. Prabhu and S. K. Sarkar, "Free-electron lasers.," CURRENT SCIENCE, VOL. 87,, pp. NO. 8, 25, OCTOBER 2004.[2] M. Tecimer, Time –Domanin analysis andtechnology of THz Free Electron Lasers, Tel –Aviv University. : Faculty of Engineering.Departamento f Electical Engineering –Physical Electronics. , 2005.[3] J. Tanabe, Iron Dominated ElectromagnetsDesign, Fabrication, Assembly and Measurements, 2006.[4] M. D. J. R. Peter Schmüser, Ultraviolet andSoft X-Ray Free-Electron Lasers - Introduction to Physical Principles, Experimental Results, Technological Challenges, Springer, 2009.[5] J. G. L. R. E. Paul P. Tesch, "Finalconstruction of the CREOL 8 mm period hybrid undulator," Nuclear Instruments and Methods in Physics Research A375, pp. 504-507, 1996. [6] R. N. Faria, L.F.C.P. Lima, Introdução aomagnetismo dos materiais, São Paulo: Livraria da Fisica, 2005.。
山东化工SHANDONGCHEMICALINDUSTRY-158-2020年第49卷核磁共振波谱课程教学探索李晓虹(苏州大学材料与化学化工学部，江苏苏州215123)摘要:核磁共振波谱作为鉴定化合物结构、组分含量、动力学参数等信息的重要手段,在化学、医药、材料等领域科研生产中起着关键作用。
其课程教学长期以来受到理论内容难、仪器开放难等因素困扰’结合苏州大学核磁共振波谱课程的双语教学实践提出了相应的对策与改进举措，探讨通过更新改进教学方法和内容，突破传统教学模式，使学生从理论联系实践,从“会用”到“用好”核磁技术’关键词:核磁共振波谱;远程虚拟终端%网络课堂中图分类号：G642O文献标识码：B文章编号：1008-021X(2020)23-0158-02Exploration of Teaching in Nuclear Magnetic Resonance Spectroscopy CourseLi Xiaohong(Colleae of Chemist—,Chemicai Enginee/ng and Materials Science of Soochow University,Suzhou215123,China) Abstract:Nuclear magnetic resonance spectroscopy(NMR),as an Onportant method of studying compound structures, component contents and kinetic parameters,plays a key rolo in the fields of chemist—,pharmaceutical indust—and materials science.For a long time,its course teaching has been troubled by the dOficulta of theo—tical content and the lack of instmmentai peacicce.Based on ihebcocnguaoieachcngpeacicceooNMR couesecn Soochow Unceeesciy,ihcspapeedcscu s eshow iobeeak iheough iheieadciconaoieachcngmodebycmpeoecngiheieachcngmeihodsand conienis,soihaisiudeniscan combcneiheoeywcih peacicceand makegood useooNMRiechnooogy.Key wordt:NMR%VNC%online coa s es核磁共振波谱作为鉴定化合物结构的重要手段，对样品无损，分辨率高,较灵敏，可获得准确的定性定量信息。
The physics of spintronics andmagnetic materials自从计算机从巨大的机器变成为我们可以手持的小电脑，存储数据的方式就一直在改变。
从最初的磁带和磁盘，到硬盘和闪存，每一种存储技术都有其优劣之处。
近年来，磁性材料和旋转电子学（spintronics）从事态中崛起。
旋转电子学是一种电子学的子领域，利用电子的自旋而不是其电荷来传输信息。
它有望改变我们的信息技术，创造出更快、更容易控制的存储器件。
磁性材料在这个过程中扮演着重要的角色，因为它们可以帮助设备存储和读取数据。
但是，怎样才能制造这种磁性材料呢？首先，我们必须了解它们的物理特性。
磁性材料基本上是由磁矩组成的材料。
磁矩是电荷旋转形成的小磁场，就像地球的磁场一样。
这些磁矩可以在整个物质中相互作用，形成像铁磁一样的长期磁性。
磁性材料中的磁矩通常来自于未成对电子的自旋。
未成对电子是电子的一种状态，在这种状态下，电子未与另一个电子成对，而是以比较自由的状态存在。
这些未成对的电子可以形成磁矩，从而创造出磁性。
但并不是所有的未成对电子都能够产生磁矩。
只有同一层中的电子能够形成磁矩。
这是由于电子在不同层中旋转的方向不同，当它们成对时会互相抵消。
为了产生磁矩，这些未成对电子必须在同一层中旋转方向一致。
一些磁性材料中，磁矩可以沿某一个特定方向对齐。
这种对齐被称为磁畴，磁畴的大小和形状取决于材料的构成和大小。
我们如何控制磁畴呢？这里就引入了旋转电子学的概念。
通过在磁性材料上增加一层非磁性材料，可以控制磁畴的方向。
这层非磁性材料称为隧道结。
它的厚度非常薄，可以被认为是一层分子，但它具有一个重要特性：它可以防止电子通过，这意味着只有在隧道结上方的磁畴是可以被控制的。
这里出现了一个重要的过程，称为磁电阻。
简而言之，磁电阻是指随着磁畴的旋转，材料的电阻也会相应地发生变化。
由于电阻发生变化，我们就可以依据电阻读取磁畴的状态。
磁畴内电子的运动决定了电阻的大小，因此，通过控制电子的运动，可以改变电阻的值。
a rXiv:h ep-ph/964438v23May1996CERN-TH/96-73The Chromomagnetic Dipole Operator and the B Semileptonic Branching Ratio M.Ciuchini 1Theory Division,CERN,Geneva,Switzerland E.Gabrielli INFN,Sezione di Roma II,Rome,Italy G.F.Giudice 2Theory Division,CERN,Geneva,Switzerland ABSTRACT We consider the possibility of having a large branching ratio for the decay b →sg coming from an enhanced Wilson coefficient of the chromomagnetic dipole operator.We show that values of BR (b →sg )up to ∼10%or more are compatible with the constraints coming from the CLEO experimental results on BR (B →X s γ)and BR (B →X s φ).Such large values canreconcile the predictions of both the semileptonic branching ratio and the charm counting with the present experimental results.We also discuss a supersymmetric model with gluino-mediated flavour violations,which can account for such large values of BR (b →sg ).CERN-TH/96-73April 19961IntroductionThe world average of all measurements of the B-meson semileptonic branching ratio is[1]BR exp SL≡BR(B→Xe¯νe)=(10.4±0.4)%.(1) This result is considerably smaller than the theoretical prediction in the parton model,where BR SL∼13–15%[2].Furthermore1/m2Q non-perturbative corrections cannot reduce the pre-dicted BR SL below12.5%[3].However it has recently been found that charm mass corrections toΓ(b→c¯c s)are large and can further reduce the theoretical prediction for BR SL[4]:BR SL= (12.0±0.7±0.5+0.9−1.2±0.2)%on-shell scheme(11.3±0.6±0.7+0.9−1.7±0.2)%(3)MS schemewhere thefirst error corresponds to the quark mass uncertainties,the second to theαs variation insimultaneous,although modest,decrease of n c[6].On the other hand,if“spectator effects”are responsible for the observed low value of the ratioτ(Λb)/τ(B d)=0.76±0.05,they then tend to increase the prediction for BR SL,making the problem even more pressing.Recently it has also been suggested[7]that the data indicate the presence of1/m Q corrections in non-leptonic decays,which are not present in HQET.This has been attributed to a possible failure of the operator product expansion near the physical cut and a corresponding violation of the local quark–hadron duality.In particular,using the phenomenological recipe of replacing the quark mass by the decaying hadron mass in the m5factor in front of all non-leptonic widths,BR SL, n c,andτ(Λb)/τ(B d)can be reconciled with their measured values[7].In this paper we discuss the effect of new physics on BR SL and n c.The possibility that large contributions toΓ(b→sg)can eliminate the disagreement between experiments and Standard Model predictions wasfirst proposed in ref.[8],and then studied in much further detail in ref.[9].Our goal here is to refine previous analyses and consider new constraints.In sect.2we perform a model-independent analysis ofΓ(b→sg)and the possible constraints coming fromΓ(B→X sγ)andΓ(B→X sφ),extending the results of ref.[9].In particular we show thatΓ(B→X sφ),in spite of its sensitivity to penguin operators,provides a poor probe of New Physics effects.In sect.3we discuss a supersymmetric model with gluino-mediatedflavour violations,first suggested by Kagan[9],which can explain a large enhancement ofΓ(b→sg).2Model-Independent AnalysisThe effective Hamiltonian relevant for∆B=1decays is given by[10]H∆B=1eff =G F2V∗cb V cs(C1(µ)Q c1(µ)+C2(µ)Q c2(µ))+(5) V∗ub V us(C1(µ)Q u1(µ)+C2(µ)Q u2(µ))−V∗tb V ts12i=3C i(µ)Q i(µ) ,where V ij are the CKM matrix elements and C i(µ)are the Wilson coefficients evaluated at the scaleµof order m b.The dimension-six local operator basis Q i is given byQ q1=(¯sαqβ)V−A(¯qβbα)V−AQ q2=(¯sαqα)V−A(¯qβbβ)V−AParameter0.950.11717455000.3161.0190.0586Table1:Central values of the input parameters used in the analysisQ3,5=(¯sαbα)V−A q(¯qβqβ)V∓AQ4,6=(¯sαbβ)V−A q(¯qβqα)V∓A3Q7,9=(¯sαbβ)V−A q e q(¯qβqα)V±A2g sQ11=m b¯sασµνV+A bαFµν.(6)16π2Here(¯q1q2)(¯q3q4)denotes current–current products,V±A indicates the chiral structure and α,βare colour indices.Moreover,g s(e)is the strong(electromagnetic)coupling constant,G Aµν(Fµν)is the gluon(photon)field strength,and the t A are the SU(N)colour matrices normalized so that T r(t A t B)=δAB/2.This Hamiltonian is known at the next-to-leading order(NLO),as far as one separately considers the current–current,gluon and photon penguin operators Q1-Q10on the one hand [11]and the magnetic-type operators Q11-Q12on the other hand[12].Unfortunately the mixing between these two classes of operators is at present known only at the leading order(LO)[13].The branching ratio of the decay b→sg is given by[14]BR(b→sg)=BR exp SL|V∗ts V tb|2πg(m/m b)|C eff11(µ)|2,(7)cwhere BR exp SL is the measured semileptonic branching ratio,the phase-space factor g(z)is givenin the Appendix,µ=O(m b)and C effis the renormalization-scheme invariant coefficient111introduced in ref.[15].With the input values given in table1,the LO Standard Model prediction isBR SM(b→sg)=(2.3±0.6)×10−3,(8) where the error is mainly due to the variation ofµbetween m b/2and2m b and to the uncertainty onαs(M Z).Inclusion of the known part of the NLO corrections reduces the central value and theµdependence,but introduces a significant scheme dependence[14].In the effective Hamiltonian approach,physics beyond the weak scale affects only the initial conditions of the Wilson coefficients,namely C i(M W).Therefore these coefficients can be used to parametrize new physics effects without referring to a specific model.In the case at hand,we assume that the initial condition of the Wilson coefficient C11(M W)is an independent variable and defineC11(M W)r g=3x2log x4(x−1)3−=0.25Γ(b→ceν)Γ(b→c¯u d′)R ud==0.25±0.10.(13)Γ(b→ceν)91011121314BR SL0.911.11.21.31.4n cFigure 1:Correlation between the semileptonic branching ratio BR SL and the number of charms per B decay n c .The solid band is the Standard Model prediction,including the theoretical uncertainties,while the dashed one is obtained assuming a BR (b →sg )=9%.The experimental data point is also shown.Here Γ(b →no charm)is the sum of all B decay widths into charmless final states different from sg .Notice that in eq.(12)we have eliminated the dependence on Γ(b →c ¯c s ),which is the main source of theoretical uncertainty.If we require that the experimental central values of BR SL and n c ,eqs.(1)and (4),lie within the theoretical uncertainty,we need 7%<BR (b →sg )<11%.This corresponds to 10.2<r g <13.1or −12.3<r g <−15.2.For instance the effect of BR (b →sg )=9%in eq.(12)is shown in fig.1(see the dashed band).We now want to perform a model-independent analysis of the constraints on r g .The first constraint comes from the observation of the inclusive decay B →X s γ.The LO expression for BR (B →X s γ)is [14,15]BR (B →X s γ)=BR exp SL |V ∗ts V tb |22πg (m c /m b )|C eff 12(µ)|2.(14)It is well known that this branching ratio has very large QCD corrections.It also has a significant theoretical uncertainty,mainly due to the scale dependence in the Wilson coefficient,to be taken into account.Also in this case,the known NLO terms decrease the central value and theµdependence,but introduce a sizeable scheme dependence,to be cancelled by the unknown terms.The dependence on r g in eq.(14)comes from the operator mixing in the QCD renormal-ization group equations.Analogously to eq.(9),we definerγ=C12(M W)12(x−1)3+x2(3x−2)log x2We thank A.Ali for pointing out this possible experimental test.–4–2–20–100102 0BR (b → sg )02410–110–210–310–310–210–10r γr g Figure 2:Correlation between the ratios r g and r γ,defined in eqs.(9)and (15).The scale on the right shows the corresponding values of BR (b →sg ).The regions outside the two oblique bands are excluded by the measured BR (B →X s γ).The region above the dashed line is excluded by the upper limit on the BR (B →X s φ),assuming ξ=1/3.However,the theoretical error is large and not completely under control in this case,so that the limit is plotted only for illustrative purpose.Finally the two oblated regions delimit the ranges allowed in the supersymmetric model with LL (dotted line)and LR (solid line)flavour mixing obtained for m ˜g >200GeV and ˜m >100GeV.theory with the factorization method.Moreover they made a strong assumption on the quark momenta distribution inside the φmeson (p s =p ¯s =p φ/2).These hypotheses result in a pure two-body decay b →sφ,while for example string fragmentation models indicate high multiplicity final states for the b →sg decay [22].The same assumptions are also used to extract the experimental limit from the measurements.Thus,constraints coming from this limit have large theoretical uncertainties and should be taken with caution.Nonetheless,in the following,we calculate the constraints in the r g -r γplane,coming from the limit on BR (B →X s φ),under the same assumptions made in refs.[20,21],which allow astraightforward calculation of the branching ratio.In terms of r g-rγ,the following expression is obtained:BR(B→X sφ)=a1|Cφ(m b)|2+a2αs(m b)Re(Cφ(m b))r g+a3αe Re(Cφ(m b))rγ+a4αs(m b)2r2g+a5α2e r2γ+a6αs(m b)αe r g rγ,(19)where the coefficients a i are functions of the masses m b,Mφ,m s.They are explicitly given in the Appendix.Beside C11and C12,eq.(19)depends on the coefficient Cφ.It appears when the matrix elements of the relevant penguin and electropenguin operators are evaluated using the factor-ization method and it is given by[20]Cφ(µ)=C eff3(µ)+C eff4(µ)+C eff5(µ)+ξ C eff3(µ)+C eff4(µ)+C eff6(µ)−13Notice that the denomination“effective coefficient”refers to completely different definitions in the case of C3−C10and C11−C12.-10-50510Z penguin 0.50.7511.251.51.752-10-50510photon penguin0.960.9811.021.041.06-10-50510gluon penguin 0.80.911.11.2-10-50510box 0.80.911.11.2Figure 3:The coefficient |C φ|as a function of C 3(M W )-C 10(M W ),normalized to the Standard Model.The eight initial conditions are parametrized in terms of the four contributions coming from the box and the g ,Z ,γpenguin diagrams.C φis quite insensitive to the initial conditions of the penguin and electropenguin operators Q 3−Q 10.In fig.3we show |C φ|as a function of these initial conditions,parametrized in terms of the contributions of the gluon,Z ,γpenguin and the box diagrams,normalized tothe Standard Model.The reason of this weak dependence is twofold.On the one hand,the largest terms in C φcome from the gluon penguin operators Q 3−Q 6,which are insensitive to their initial conditions because the large mixing with Q 1−Q 2dominates their renormalization group evolution down to µ=O (m b ).On the other hand,the effective coefficients C eff i get a large NLO contribution from the O (αs )matrix elements,which do not depend on the initial conditions of the Wilson coefficients.This implies that BR (B →X s φ)in general gives a poor probe of new physics effects,contrary to what is often stated in the literature.Therefore,it is reasonable to assume C φas a constant in the analysis,so that the BR (B →X s φ)could be used to put constraints in the r g −r γplane.Unfortunately this constraint suffers from large theoretical uncertainties.For example the predicted branching ratio changesby a factor of2as we varyξbetween1/2and1/3,which is a popular way to account for the uncertainty of the factorization method[20].Moreover the assumption on the decay kinematics is not under control and the related uncertainty is not quantifiable.Just for illustrative purposes we show infig.2the constraint coming from eq.(19),assumingξ=1/3.For larger values ofξ,the bound on r g from B→X sφbecomes more stringent,disfavouring even further the solutions of the BR SL–n c problems corresponding to positive r g.However if we assign an overall uncertainty of a factor of3in the prediction of the branching ratio,any significant bound on r g disappears.An enhanced b→sg decay rate also affects the exclusive decays B→Kπ[21].We estimate BR(B−→¯K0π−)≃10−5(1+0.1r g)2,which corresponds to an effect of order1for|r g|∼10.Again the theoretical uncertainty of this prediction is large and not under control,so we prefer not to show this constraint infig.2.We have seen how present constraints allow large enhancements of BR(b→sg).Measure-ments of BR(B→X sγ)require,however,a precise correlation between r g and rγ.The main difficulty to solve the BR SL–n c problem in terms of new physics is to explain this correlation. We now turn to a discussion of models in which this is possible.3An Illustrative ModelThe suggestion that anomalously large BR(b→sg)can explain a reduction of BR SL wasfirst made in ref.[8],where it was assumed that the new effective bsg interaction is mediated by virtual charged Higgs boson exchange.This possibility is now ruled out by a combination of the constraints from B→Xτ¯ν,B→X sγ,and Z→b¯b.The main difficulty of models where the bsg interaction arises from charged-Higgs exchange,shared by most other models with weakly-interacting new particles,is that generically r g∼rγ.Constraints from BR(B→X sγ) then allow only small enhancements of r g.The possibility thatflavour-changing quark–squark–gluino interactions can generate large coefficients for the chromomagnetic operator wasfirst suggested in ref.[9].Now the loop generating O11has a large Casimir factor,which is not present in the loop generating O12,and one obtains r g/rγ∼5–7.This allows a significant enhancement of b→sg,especially if weconsider solutions with negative rγ.We have in mind the case in which the squark mass matrix is not diagonal in the quark mass eigenbasis.This situation is generic in supersymmetric models derived from supergravity with non-minimal K¨a hler metric.For simplicity we consider separately two possibilities.In the first case,we assume thatflavour non-diagonal entries of the squark mass matrix appear only in the left sector and there is no left–right squark mixing.The new contributions to the Wilson coefficients C11and C12,evaluated at the scale of supersymmetric particle masses,are[24]C11=Z36(x−1)3+x2(x−9)log xm2˜g3i=1U∗ib U is f2(m2˜g/˜m2i)(23)f2(x)=2x(−2x2−5x+1)9(x−1)4(24)Z≡√V∗tb V ts G F(25)Here m˜g is the gluino mass and˜m2i are the eigenvalues of the down-squark squared-mass matrix, which is diagonalized by the3×3unitary matrix U.If˜m i are nearly degenerate,eqs.(21)and (23)can be Taylor-expanded around the common squark mass˜m:C11=Z δ˜m2bL s L36(x−1)4+x(x2−15x−18)log x˜m4f3(m2˜g/˜m2)(28)f3(x)=2(−17x2−8x+1)9(x−1)5(29)Hereδ˜m2bL s L≡ U∗ib U is˜m2i corresponds to theflavour non-diagonal mass insertion.In the second case we consider,the down-squark mass matrices for the left and right sectors are both diagonal,but there areflavour non-diagonal left–right(LR)mixing terms.Since these terms are not generated by supersymmetry breaking,in the limit of vanishing Yukawa couplingconstants,we will assume here that they are proportional to the corresponding Yukawa coupling.In this case,the mass-insertion approximation is always adequate and the new contributions to the Wilson coefficients C 11and C 12areC 11=Zδ˜m 2b R s Lx −2(x +11)3(x −1)4(31)C 12=Zδ˜m 2b R s Lx 4(5x +1)9(x −1)4 .(33)The two cases here considered are the simplest because they generate only operators with the same chiral structure as in the Standard Model.They also describe the generic features of more complicated squark mass matrices.By varying the relevant supersymmetric parameters under the requirement that all squark masses are larger than 100GeV and m ˜g >200GeV,we find that the new interactions can generate values of r g and r γwithin the regions illustrated in fig.2.The prediction has a strong correlation in the r g –r γplane because the ratio r g /r γdepends on the supersymmetric parameters only weakly,through the loop functions.Thus,in spite of its generic features,the model can make a rather precise prediction of this ratio.It is interesting that it is indeed possible to reach a region in which b →sg has the correct enhancement to solve the BR SL –n c puzzle.The solution always corresponds to the case in which the signs of both C 11and C 12are opposite to the Standard Model results.In the case of left–left (LL)mixings this region is achieved when the mixing between the s and b squark is maximal 4and when the lightest squark mass 5is around 100GeV and m ˜g around 200GeV.This means that supersymmetry could be soon discovered at the Tevatron,but no light squark has to be expected at LEP2.Similar conclusions apply to the case of LR mixing.However if the LR mixing were not proportional to m b ,the same effects could be obtained for much heavier squarks and gluinos,although the existence of colour-breaking minima could impose significant constraints on the parameterspace.Finally notice that,in the case of a very light gluino(m˜g∼1GeV)the ratio r g/rγcan become much larger than that shown infig.2,especially for LR mixings.In this case it is possible to have r g as small as−10for positive values of rγ,and almost reach the shaded region infig.2corresponding to positive rγand negative r g.Given a definite model offlavour violation,we can consider more tests on its consistency than in the case of the model-independent analysis of sec.2.We now assume that gluino-mediated flavour violations occur only between the second and third generation of the down quark–squark sector and consider different processes with|∆B|=0,which can be of experimental interest.The|∆B|=2transitions will affect the B s–¯B s mixing.For LL mass insertions,the new contribution to∆m B s is[24]∆m B s=4˜m2 δ˜m2b L s L216 (−2x3+27x2+144x+11)(x−1)5 .(35)This contribution is much larger than the Standard Model one,making the discovery of B s–¯B s mixing even more arduous.However,for x≃2.4,the function G(x)has a zero and therefore, for particular values of the squark and gluino masses,we can reduce the total contribution to∆m B s.Nevertheless,the generic prediction of the model is that B s–¯B s mixing will not be discovered soon.The|∆B|=1transitions can induce theflavour-changing decay Z→¯bs.For LL transitions [26]BR(Z→¯bs)=αα2s m Z3sin2θW 2 U∗ib U is F(˜m2i,m2˜g,m2Z) 2(36)F(˜m2i,m2˜g,m2Z)= 10dx 1−x0dy log ˜m2i(x+y)+m2˜g(1−x−y)−m2Z xyFinally we consider FCNC decay processes of B mesons,such as B→X sν¯νand B→X sℓ+ℓ−.It is known[24]that gluino-mediated interactions do not affect the Z penguin operator. Indeed,the effective b-s-Z vertex turns out to be proportional to the b-s-γvertex.QED gauge invariance then implies that the Z penguin is suppressed by a factor q2/m2Z,where q2 is the momentum transfer.Because of this suppression we do not expect new contributions to B→X sν¯ν.On the other hand,the process B→X sℓ+ℓ−receives new contributions from the gluino-mediatedγpenguin operator and from the electromagnetic dipole operator,which has here a sign opposite to the Standard Model result.This change of sign implies important modifications both in the rate and the lepton asymmetries of B→X sℓ+ℓ−[28].The new contribution to theγpenguin is however rather modest.Wefind that LL transitions giveZC e=12x4log x81(x−1)3−(¯sαbα)V−A(¯e e)V.(41)2πUsing the mass-insertion approximation and taking for simplicity m2˜g/˜m2i=1,eq.(39)can be rewritten asC eFinally we have discussed how a supersymmetric model with gluino-mediatedflavour viola-tions can account for a large value of BR(b→sg),consistently with all other constraints from ∆B=1and∆B=2FCNC processes.The theory has a rather precise correlation between the predictions for r g and rγ,which is fairly independent of the specific model assumptions.Al-though the enhancement of BR(b→sg)is achieved only for particular values of the parameter space and it is evidently not a general consequence of the model,it is interesting to know that supersymmetry can potentially predict BR(b→sg)≃5–10%,and solve the BR SL–n c puzzle. Future experiments will certainly be able to test this scenario.Note addedAfter completion of this work,we received a note by A.Kagan who informed us that their new results on B→X sφagree with those presented in this paper[29].AcknowledgementsWe had useful discussions with A.Ali,P.Ball,G.Martinelli and M.Neubert.One of us,E.G., thanks the CERN Theory Division and the Department of Physics,University of Southampton, for their kind hospitality during the completion of this work.AppendixIn this appendix we report on the result of our calculation of BR(b→sφ).As in refs.[20,21], we assume a pure two-body decay and use the factorization method to estimate the relevant matrix elements.We have computed both the contributions of Q11and Q12.The amplitude we obtain isA(b→sφ)=−G F2V tb V∗ts igφǫµ 2Cφ(m b)¯sγµLb+αs(m b)m b2N2C11(m b)[m b¯sγµLb+ 6+4m2s M2φ ¯sγµRb−4m b m s 8πk2C12(m b) 9m b¯sγµLb− 10−4m2s−2m 2b +2M 2φ−m 2sM 2φp µb ¯s Lb ,(43)where k 2=(m 2b +m 2s −M 2φ/2)/2,C φ(m b )has been introduced in eq.(20)and g φisdefined by φ|¯s γµs |0 =ig φǫµ.This result does not fully agree with those of refs.[20,21]6.From eq.(43),we obtain the branching ratioBR (b →sφ)=Γ(b →sφ)|V cb |26π2g 2φBR exp SL M 2φ−4M 2φm 2b M 2φ+2m 2s M 2φ+αs (m b )k 2 N 2−1M 2φ+4m 4b M 2φ−23m 2s+αe k 219m 2b −20m 2b m 2sM 2φ−23M 2φ+16m 4s 8πk 2 2 N 2−12m 2b M 2φ−4m 2b m 6s M 2φ−54m 2b m 2s −19m 4b −4m 4b m 4s M 4φ+8m 6b2M 2φm 2s −9M 4φ−8m 6s 8πk 2 2 −177M 4φ+112m 2b m 4s M 4φ−96m 4b m 2s M 4φ+8m 6b 2M 2φm 2s −25M 4φ−8m 6s8πk 2αe C 12(m b )2N 2−41m 2b M 2φ−8m 2b m 6s M 2φ−212m 2b m 2s +10m 4b −8m 4b m 4s M 2φ+8m 6b m 2sM 2φ−65M 2φm 2s +15M 4φ+8m 8sM 2φ+90m 4s ,(44)where N is the number of colours,λ(m 1,m 2,m 3)=(1−m 2/m 1−m 3/m 1)2−4m 2m 3/m 21,g (z )=1−8z 2+8z 6−z 8−24z 4ln(z )is the phase-space correction and Ω(z,µ)≃1−2αs (µ)4 (1−z )2+36Numerically our branching ratio is ∼25%smaller,including the effect of the residual scheme dependence.References[1]T.E.Browder,preprint UH-511-893-95,to appear in the Proceedings of the Int.EurophysicsConf.on High Energy Physics,Brussels,Belgium,July1995[hep-ex/9602009];T.Skwarnicki,preprint HEPSY-95-05,to appear in the Proceedings of the17th Int.Conf.on Lepton-Photon Interactions,Beijing,China,August1995[hep-ph/9512395].[2]G.Altarelli and S.Petrarca,Phys.Lett.B261(1991)303.[3]I.Bigi,B.Blok,M.A.Shifman and A.Vainshtein,Phys.Lett.B323(1994)408.[4]E.Bagan,P.Ball,V.M.Braun and P.Gosdzinsky,Nucl.Phys.B432(1994)3;Phys.Lett.B342(1995)362;Erratum[hep-ph/9602364];see also M.Neubert,preprint CERN-TH/95-307,to appear in the Proceedings of the17th Int.Conf.on Lepton-Photon Interactions,Beijing,China,August1995[hep-ph/9511409].[5]I.Dunietz,P.S.Cooper,A.F.Falk and M.B.Wise,Phys.Rev.Lett.73(1994)1075.[6]M.Neubert and C.T.Sachrajda,preprint CERN-TH/96-19[hep-ph/9603202].[7]G.Altarelli,G.Martinelli,S.Petrarca and F.Rapuano,preprint CERN-TH/96-73[hep-ph/9604202].[8]B.Grzadkowski and W.-S.Hou,Phys.Lett.B272(1991)383.[9]A.L.Kagan,Phys.Rev.D51(1995)6196.[10]A.J.Buras,M.Jamin,utenbacher and P.H.Weisz,Nucl.Phys.B370(1992)69and375(1992)501.[11]A.J.Buras,M.Jamin,utenbacher,Nucl.Phys.B400(1993)37and75;M.Ciuchini,E.Franco,G.Martinelli and L.Reina,Nucl.Phys.B415(1994)403.[12]M.Misiak and M.M¨u nz,Phys.Lett.B344(1995)308.[13]M.Ciuchini, E.Franco,G.Martinelli,L.Reina and L.Silvestrini,Phys.Lett.B316(1993)127;M.Ciuchini,E.Franco,L.Reina and L.Silvestrini,Nucl.Phys.B421(1994)41;G.Cella,G.Curci,G.Ricciardi and A.Vicer´e,Nucl.Phys.B431(1994)417;M.Misiak,Nucl.Phys.B439(1995)461.[14]M.Ciuchini, E.Franco,G.Martinelli,L.Reina and L.Silvestrini,Phys.Lett.B334(1994)137.[15]A.J.Buras,M.Misiak,M.M¨u nz and S.Pokorski,Nucl.Phys.B424(1994)374.[16]G.Buchalla,I.Dunietz and H.Yamamoto,Phys.Lett.B364(1995)188.[17]M.S.Alam et al.(CLEO Collaboration),Phys.Rev.Lett.74(1995)2885.[18]A.Ali and C.Greub,work in progress.[19]K.W.Edwards et al.(CLEO Collaboration),preprint CLEO-CONF-95-8,EPS0162(1995).[20]N.G.Deshpande and X.-G.He,Phys.Lett.B336(1994)471.[21]N.G.Deshpande,X.-G.He and J.Trampeti´c,preprint OITS-582[hep-ph/9509346].[22]J.Swain,preprint NUB-3101[hep-ph/9501415].[23]G.Kramer,W.F.Palmer and H.Simma,Nucl.Phys.B428(1994)77.[24]S.Bertolini,F.Borzumati,A.Masiero and G.Ridolfi,Nucl.Phys.B353(1991)591.[25]J.Hauser(CDF Collaboration),Proceedings of the10th Topical Workshop on Proton-Antiproton Collider Physics,Batavia,IL,May1995,edited by R.Raja and J.Yoh(AIP Conference Proceedings,357);S.Abachi et al.(D0Collaboration),preprint FERMILAB-CONF-95/193-E,to appear in the Proceedings of the Int.Europhysics Conf.on High Energy Physics,Brussels,Belgium, July1995.[26]G.Gamberini and G.Ridolfi,Nucl.Phys.B287(1987)304.[27]Y.Khokhlov,private communication.[28]A.Ali,G.F.Giudice and T.Mannel,Z.Phys.C67(1995)417.[29]A.Kagan and A.Perez,work in progress.。
